Various apparatus and methods for the continuous preparation of aqueous polymer solutions, including aqueous solutions of hydrolyzed polyacrylamides, heretofore have been proposed. One such method is disclosed in U.S. Pat. No. 2,820,777. The method of that patent utilizes a single reaction vessel, and comprises polymerizing and hydrolyzing acrylamide monomer in a single-step to obtain a composition containing amide and carboxylate groups. The method is carried out by forming two solutions, one of which comprises acrylamide monomer and water, and the other of which comprises a polymerization catalyst, an alkali metal hydroxide, and water. The hydroxide is present in an amount ranging between about 0.01:1 to about 0.25:1 mols per mole of acrylamide monomer. The solutions are pumped separately, at an equal volume rate, into a common reactor. The residence time of the reactants in the reactor may, according to the patent, vary from 10 minutes to 5 hours. While the patent suggests that the properties of the end products can be altered by varying the proportions of the reactants and the conditions under which polymerization and hydrolyzation are simultaneously carried out, the haphazard, all-in-one-pot nature of the method makes it unsuitable for the preparation of aqueous polymer solutions for use in secondary and tertiary oil recovery procedures where it is necessary to provide an end product having predictable properties from the standpoint of its ability to meet the performance demands of an oil-bearing formation or reservoir. U.S. Pat. No. 4,110,521 is also directed to apparatus and a method for the continuous preparation of aqueous polymer solutions. The apparatus disclosed in the patent is relatively complex and costly. More specifically in this connection, the apparatus incorporates large numbers of static mixers, and requires the extensive use of pumps and temperature control means throughout the system, all of which make it impractical and unsuitable for the on-site preparation of aqueous polymer solutions of the type employed in the secondary and tertiary recovery of oil.